The unexpected sudden rainstorm in the middle and late August caused the phenomenon of premature withering in some cotton fields, which caused a serious reduction in cotton production. At the beginning of August last year, the author inspected cotton in Jianghan County, Hubei Province. Generally, about 30 bells were boiled and more than 50 were grown. Normal growth was observed in the cotton fields, but the two fell on August 15-16 and August 28. In heavy rains, local rainfall reached 150 mm or more. After the rain, some cotton fields hired local plants and wilted. After two or three days, they turned brown and brown and died. Some cotton plants became blue and dry after wilting from top to bottom.
First, the relationship between early drying and related factors.
1. Related to the species, According to the survey of 54 cotton varieties currently planted in Hubei by the Qianxin Cotton Research Institute of Guoxin Cotton Research Institute, under the same conditions, the difference in dead seedlings between the varieties is significant, and the number of dead bells is generally less, and the growth period is relatively small. Longer dead seedlings were lighter; there were more bells and knots, and dead seedlings that were mature earlier were heavier; those that were resistant to yellowing and wilt disease were lighter, and those that were susceptible to disease were heavier.
2. In relation to the topography, multiple surveys have shown that the groundwater level is relatively high (less than one meter), where there is poor drainage, where dead seedlings are heavy. According to Hu Gaosheng, head of Taihu Farm, the head of ten mu of demonstration plots surveyed, the terrain in the north is relatively unpleasant, drainage is poor, and the dead seedlings are heavier, while the south head has a higher drainage and is more relaxed, with no apparent occurrence of premature clouding.
3. The relationship with fertilization, according to the survey, the topdressing of cotton dressing is generally repeated in the flowering period, and the fertilizing time is generally on July 15-20, once a topdressing amount of 20-25 kg urea, and there is no obvious occurrence of early drying after this heavy rain. relationship. However, fertilization is insufficient, and the relatively weak sandy cotton fields are heavy. In addition, some farmers have had top-dressing fertilizers that are too late to be top-dressed, and they are often top-dressing, and they are often heavier after recovering from the rainy cotton fields. In addition, in the southern cotton fields, there is a general shortage of potassium, and in the cotton fields with insufficient potassium fertilizer, early dead seedlings occur more severely.
Second, the prevention and remedial measures of early drying of cotton fields.
1. Selection of anti-mite and disease-resistant varieties This is the basis for prevention and treatment of early-ripening. The selection of varieties should be adapted to local conditions. For early transplanting, varieties with longer growing period should be selected, so that the peak season of Chengling misses the rainstorm season; after wheat, rape is recommended. Planting should select good varieties with early maturity so as to prevent ripening from affecting yield too late.
2, dredge four ditch, do a good job of drainage project. The results of last year's survey showed that where the drainage works are done well, the occurrence of early dry weather is light, especially in the areas with higher groundwater level, and the groundwater level is higher. The excavation of the earth will enable the Xianggou, the horizontal trench, the vertical trench, and the main trench to reach 20, 30, 50, 100 cm is appropriate, so that after the rain, smooth drainage.
3. Take effective management measures to postpone the root ageing period. The field management of cotton after flowering is mainly rooted in cultivating roots, delaying root senescence and preventing the occurrence of early weeping. After flowering, the cotton should not be intensively cultivated, and the top dressing should adopt the principle of a small number of times. When the amount of top dressing is relatively large, it is appropriate to use it after rain or after pouring, and the high-yielding cotton field bolls with fertilizers are applied twice in two. , The first flower, once the bell is in full bloom, the top dressing should not be too close to the root, and the deep application should be in the ditch. The cotton in the 7th and the 8th will enter the peak of the bell, and the top fertilizer per hecter will cover 5-7.5 kg. Relieve negative root extraction. Spray foliar fertilizer once every 7 days. The best solution is 2% compound fertilizer.
4, increase potassium fertilizer. Potassium use in the south is generally about 20 kg per mu, and about 30 kg in high-yielding fields. If potassium is insufficient, flower and bell fertilizers have to be filled in, potassium fertilizers are lost in August, and 0.3% phosphoric acid is sprayed every 7 days. Hydrogen potassium once.
5. Recovery and field management after the occurrence of early drought. After the occurrence of early drought, it is necessary to take corresponding measures according to the degree of occurrence and causes. First, drainage should be carried out to reduce waterlogging. For lighter ones, the peach should be dried in a timely manner, and the dead plants should be removed to increase the intensity of ventilation and lightening in the fields. Reduce the humidity in the field and restore the normal growth of the undead cotton as soon as possible through field management. The flooding caused by fertilizer damage should be watered in time to reduce the field concentration and promote the normal growth of cotton plants.
Electronic Ballast For Hot Cathode UV Lamp&Amalgam Lamp
Electronic Ballast For Hot Cathode UV Lamp&Amalgam Lamp, Electronic Ballast For Hot Cathode UV Lamp, Electronic Ballast For Amalgam Lamp
Ningbo Sunfine UV lighting Co.,ltd. , http://www.uvlightings.com